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S J Noga

Publications and source records attributed to S J Noga.

At least 19 recordsLinked to original sources
PubMed2001

Long-term results of blood and marrow transplantation for Hodgkin's lymphoma.

PURPOSE: To evaluate the long-term outcome after allogeneic (allo) and autologous (auto) blood or marrow transplantation (BMT) in patients with relapsed or refractory Hodgkin's lymphoma (HL). PATIENTS AND METHODS: We analyzed the outcome of 157 consecutive patients with relapsed or refractory HL, who underwent BMT between March 1985 and April 1998. Patients <or= age 55 with HLA-matched siblings were prioritized toward allo BMT. The median age was 28 years (range, 13 to 52 years) for the 53 allo patients and 30.5 years (range, 11 to 62 years) for the 104 auto patients. RESULTS: The median follow-up after BMT for surviving patients was 5.1 years (range, 1 to 13.8 years). For the entire group, the probabilities of event-free survival (EFS) and relapse at 10 years were 26% (95% confidence interval [CI], 18% to 33%) and 58% (95% CI, 48% to 69%), respectively. According to multivariate analysis, disease status before BMT (sensitive relapse if responding to conventional-dose therapy or resistant disease if not) (hazard ratio [HR] = 0.39, P < .0001) and date of BMT (HR = 0.93, P = .004) were independent predictors of EFS, whereas only disease status (HR = 0.35, P < .0001) influenced relapse. There was a trend for probability of relapse in sensitive patients to be less after allo BMT at 34% (range, 8% to 59%) versus 51% (range, 36% to 67%) for the auto patients (HR = 0.51, P = .17). There was a continuing risk of relapse or secondary acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) for 12 years after auto BMT, whereas there were no cases of secondary AML/MDS or relapses beyond 3 years after allo BMT. CONCLUSION: There seems to be a clinical graft-versus-HL effect associated with allo BMT. Allo BMT for HL also seems to have a lower risk of secondary AML/MDS than auto BMT. Thus, allo BMT warrants continued study in HL.

Adolescent↗
PubMed2001

Allogeneic bone marrow transplantation in patients with sensitive low-grade lymphoma or mantle cell lymphoma.

PURPOSE: To report survival outcomes of allogeneic BMT in patients with low-grade lymphoma or mantle cell lymphoma (MCL). PATIENTS AND METHODS: Thirty-five patients with low-grade lymphoma (48%), chronic lymphocytic leukemia (26%), or MCL (26%) underwent myeloablative allogeneic BMT from HLA-identical siblings at the Johns Hopkins Oncology Center. Patients had a median age of 46 years, a median of 2 prior treatments, and 31% were in complete remission at the time of transplantation. The preparative regimen was cyclophosphamide/total body irradiation for most patients. All grafts were T-cell depleted by counter flow centrifugal elutriation with CD34+ augmentation. RESULTS: The incidence of acute GVHD grade >2 was 6% and of grades 1 to 2 was 37%. The incidence of chronic GVHD was 6%. The median follow-up time was 25 months. The rate of event-free survival (EFS) was 50% (95% confidence interval [CI], 33%-66%). Only 1 patient relapsed. The transplantation-related mortality (TRM) was 46% for all patients. The TRM was 86% for patients with resistant disease and 14% for patients with sensitive disease and <2 prior treatments; rates of EFS were 0% (95% CI, 0%-0%) and 79% (95% CI, 47%-93%), respectively. CONCLUSION: These data show that, with T-cell depletion, the TRM and relapse rates are modest for patients with sensitive disease and <2 prior treatment courses. Thus, if there is a role for allogeneic BMT in the management of patients with these tumors, it is early in the course of the disease.

Adult↗
PubMed2001

CD34 selection using three immunoselection devices: comparison of T-cell depleted allografts.

BACKGROUND: T-cell depletion of allografts markedly reduces the incidence of GvHD following BMT. The approach taken at our Center has utilized the physical separation method of counterflow centrifugal elutriation (CCE), augmented by recovery of stem cells from lymphocyte-rich fractions by immunoaffinity selection of CD34(+) stem cells. We wanted to compare the performance characteristics of three commercially available selection devices, as well as the clinical outcomes of patients who received allografts engineered by the different devices. METHODS: BM allografts were prepared for patients undergoing BMT for hematologic malignancies. BM cells were separated into lymphocyte-rich and lymphocyte-depleted fractions using CCE, followed by recovery of CD34(+) cells from the lymphocyte-rich fraction using one of three immunoselection devices [CellPro CEPRATE, Nexell Isolex 300i (software version 2.5) and AmCell CliniMACS]. Allografts consisted of the lymphocyte-depleted fraction plus the CD34-selected fraction. RESULTS: Yields of CD34(+) cells were comparable for the three devices. However, there were significant differences in purity (CEPRATE < Isolex 300i < CliniMACS) and time from start of fractionation to infusion (CEPRATE < CliniMACS < Isolex 300i). More technical problems were encountered with the Isolex 300i device. Allograft compositions were comparable. Transplant outcomes (engraftment and incidence of GvHD) also were comparable. DISCUSSION: Qualitatively and quantitatively, allografts prepared with the CEPRATE, Isolex 300i (v 2.5) and CliniMACS devices should be considered comparable for use in this setting and probably also for direct T-cell depletion of BM.

Adolescent↗
PubMed2001

Using point-of-care CD34 enumeration to optimize PBSC collection conditions.

BACKGROUND: A PBSC graft containing 4-5 x 10(6) CD34(+) cells/kg is considered optimal in terms of durable engraftment. Tracking CD34 kinetics via point-of-care testing during PBSC mobilization could determine which (and when) patients will yield an optimal product. We evaluated whether microvolume fluorimetry (MVF) would be useful in optimizing PBSC mobilization/harvest and if it will shorten our standard 6 h collection. METHODS: Absolute CD34 values were obtained using the IMAGN 2000 and STELLer CD34 assay (50 microL sample volume). Peripheral blood (PB) CD34 values from 30 patients undergoing PBSC mobilization were used to generate a PB CD34-based algorithm that would predict collection day/duration of apheresis. The algorithm was then used prospectively to collect PBSC products on 50 hematologic malignancy (HM) patients. RESULTS: Using the algorithm, patients were assigned to either a 6 (11-20 CD34/microL), 4 (21-49 CD34/microL) or 2 (> or = 50 CD34/microL) h collection. Patients with a CD34 value < or = 10/microL were re-tested. All patients (n = 43) predicted to mobilize reached the optimal CD34 (4-5 x 10(6)/kg) value with 1.0 apheresis procedure; seven patients had < or = 10/microL (nonmobilizers). The majority (75%) had apheresis charges decreased by 33-66%; 47% only required a 2 h procedure and 28% required 4 h. All patients demonstrated rapid trilineage engraftment. DISCUSSION: Absolute PB CD34 measurement using MVF offers a rapid and reliable approach to obtaining optimal PBSC products with minimal technical expertise. Although not a replacement for conventional flow cytometry, it meets the requirements for a point-of-care procedure.

Algorithms↗
PubMed2000

Human megakaryocytes and platelets contain the estrogen receptor beta and androgen receptor (AR): testosterone regulates AR expression.

Gender differences in vascular thromboses are well known, and there is evidence that platelets may be involved in these differences and that sex hormones affect platelet function. We characterized the expression of the estrogen receptor alpha (ER alpha), estrogen receptor beta (ER beta), progesterone receptor (PR), and androgen receptor (AR) in the megakaryocyte lineage. Megakaryocytes generated ex vivo from normal human CD34(+) stem cells contained RNA for ER beta and AR, which increased with cell differentiation. Platelets and human erythroleukemia (HEL) cells also contained ER beta and AR transcripts. No ER alpha or PR messenger RNA or protein was detected in the megakaryocyte lineage. Immunofluorescence microscopy showed that ER beta protein was present in glycoprotein (GP) IIb(+) megakaryocytes and the HEL megakaryocytic cell line in a predominantly cytoplasmic location. AR showed a cytoplasmic and nuclear distribution in GPIIb(+) and GPIIb(-) cells derived from CD34(+) cells and in HEL cells. Western immunoblotting confirmed the presence of ER beta and AR in platelets. Megakaryocyte and HEL AR expression was up-regulated by 1, 5, and 10 nmol/L testosterone, but down-regulated by 100 nmol/L testosterone. These findings indicate a regulated ability of megakaryocytes to respond to testosterone and suggest a potential mechanism through which sex hormones may mediate gender differences in platelet function and thrombotic diseases.

Antigens, CD34↗
PubMed2000

Human herpesvirus 8 (KSHV) contamination of peripheral blood and autograft products from multiple myeloma patients.

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), has recently been identified within the bone marrow dendritic cells of multiple myeloma (MM) patients. This virus contains homologues to human cytokines such as IL-6 that could potentially stimulate myeloma cell growth and contribute to disease pathogenesis. Since mobilization chemotherapy may increase circulating dendritic cell numbers, we searched for HHV-8 in peripheral blood mononuclear cells (PBMCs) before and after mobilization chemotherapy given to MM patients. Furthermore, we determined if autograft purging using the CEPRATE SC device would reduce the percentage of HHV-8 infected stem cell products. Only two of the 39 PBMC samples collected prior to mobilization chemotherapy contained PCR detectable virus, yet nine of 37 PBMCs collected on the first day of leukapheresis had detectable HHV-8 (P = 0.016). HHV-8 was more frequently identified in autograft products before vs after Ceprate SC selection (40% vs 15%, P = 0.016). Although the role HHV-8 plays in myeloma pathogenesis remains unclear, these results imply that mobilization chemotherapy increases the numbers of circulating HHV-8-infected dendritic cells within the peripheral blood. In addition, CD34 selection of autograft products in MM patients may reduce the reintroduction of virally infected cells following high-dose chemotherapy. Bone Marrow Transplantation (2000) 25, 153-160.

Antigens, CD34↗
PubMed2000

Autologous graft-versus-host disease induction in advanced breast cancer: role of peripheral blood progenitor cells.

The purpose of the present study was to investigate the impact of the use of peripheral blood progenitor cells (PBPCs) on the induction of autologous graft-versus-host disease (GVHD) in patients with advanced breast cancer. 14 women with stage IIIB and 36 women with stage IV breast cancer received cyclosporine (CsA) 2.5 mg kg-1 i.v. daily, d 0-28, and interferon-gamma (IFNg) 0.025 mg/m2 s.c. qod, d7-28, following PBPC-T +/- bone marrow transplantation (BMT). Preceding high-dose chemotherapy consisted of cyclophosphamide 6 g/m2 and thiotepa 800 mg/m2. Histologically proven > or = grade II cutaneous GVHD was induced in18/50 (36%) of patients and was independent of the source of haematopoietic support. In vitro studies showed that post-transplant, 76% of patients had developed auto-cytotoxicity against their own pre-transplant PHA-lymphoblasts. A significant correlation between the occurrence of GVHD > or = grade II and cytolysis was observed in the NK cell-line K562 and the T47D breast cancer cell-line. With a median follow-up of 2(1/2) years, the overall survival (OS) is 58%, the disease-free survival (DFS) 26%, both independent of the development of GVHD and similar to what has been observed in other studies on high-dose chemotherapy in advanced breast cancer. It therefore remains unclear whether the induction of autologous GVHD with the occurrence of auto-cytotoxic lymphocytes can result in an anti-tumour effect in this group of patients.

Adult↗
PubMed2000

Graft engineering.

Improvements in supportive care, antimicrobials, immunosuppressant therapy, and health care delivery have shifted the emphasis in hematopoietic stem cell transplantation toward raising cure rates and improving the quality of life in the years that follow transplantation. Many large centers have significantly reduced the morbidity of allogeneic transplantation by effecting a decrease in acute and chronic graft-versus-host disease. Extension of this modality through the use of unrelated donors, peripheral blood stem cell products, and HLA-mismatched family members has again introduced significant posttransplantation complications. Conversely, the posttransplantation morbidity of autologous transplantation is minimal, but the chances of remaining in long-term remission are still inferior to those afforded by allogeneic hematopoietic stem cell transplantation. One approach developed to reduce these long-term complications is referred to as "graft engineering." Through the use of successive clinical protocols, hematopoietic grafts and host immune properties can be manipulated in a stepwise fashion using several outcome parameters to judge efficacy. This report details one center's experiences with graft engineering over 12 consecutive years of clinical trials and speculates on future approaches that may supplant transplantation in the new millennium.

Acute Disease↗
PubMed1999

Ex vivo cultured megakaryocytes express functional glycoprotein IIb-IIIa receptors and are capable of adenovirus-mediated transgene expression.

Investigation of the molecular basis of megakaryocyte (MK) and platelet biology has been limited by an inadequate source of genetically manipulable cells exhibiting physiologic MK and platelet functions. We hypothesized that ex vivo cultured MKs would exhibit agonist inducible glycoprotein (GP) IIb-IIIa activation characteristic of blood platelets and that these cultured MKs would be capable of transgene expression. Microscopic and flow cytometric analyses confirmed that human hematopoietic stem cells cultured in the presence of pegylated recombinant human MK growth and development factor (PEG-rHuMGDF) differentiated into morphologic and phenotypic MKs over 2 weeks. Cultured MKs expressed functional GPIIb-IIIa receptors as assessed by agonist inducible soluble fibrinogen and PAC1 binding. The specificity and kinetics of fibrinogen binding to MK GPIIb-IIIa receptors were similar to those described for blood platelets. The reversibility and internalization of ligands bound to MK GPIIb-IIIa also shared similarities with those observed in platelets. Cultured MKs were transduced with an adenoviral vector encoding green fluorescence protein (GFP) or beta-galactosidase (beta-gal). Efficiency of gene transfer increased with increasing multiplicities of infection and incubation time, with 45% of MKs expressing GFP 72 hours after viral infection. Transduced MKs remained capable of agonist induced GPIIb-IIIa activation. Thus, ex vivo cultured MKs (1) express agonist responsive GPIIb-IIIa receptors, (2) are capable of expressing transgenes, and (3) may prove useful for investigation of the molecular basis of MK differentiation and GPIIb-IIIa function.

Adenoviridae↗
PubMed1999

Acute bleeding after allogeneic bone marrow transplantation: association with graft versus host disease and effect on survival.

BACKGROUND: Hemorrhagic complications are frequently implicated clinically for the high morbidity and mortality of acute graft versus host disease (GVHD), however, only few reports characterize the incidence and timing of bleeding in relation to GVHD, and essentially no study has quantified the effect of bleeding on survival of allogeneic patients with GVHD. This study examines the association of bleeding with acute GVHD and the effect of both complications on survival. METHODS: A total of 463 allogeneic patients transplanted at the Johns Hopkins Hospital, were included in the study. Bleeding evaluation was based on daily scores of intensity and blood transfusions. All bleeding sites were recorded. GVHD staging was defined by the extent of rash, serum bilirubin, diarrhea, and confirmatory histology. RESULTS: The incidence of GVHD was 27.4%, bleeding occurred in 40.2%. The incidence of bleeding was higher in patients with GVHD as compared with non-GVHD, and correlated with GVHD severity. The higher bleeding incidence in GVHD was due to gastrointestinal hemorrhage, hemorrhagic cystitis, and pulmonary hemorrhage. While the majority of bleeding (51/75) in non-GVHD patients initiated within 30 days after bone marrow transplantation (BMT), only 32.3% (21/65) of the bleeding in the GVHD group initiated within 30 days, and the risk for bleeding continued until day 100. Bleeding was a late event compared to GVHD, however, most bleeding episodes were associated with active GVHD. Both GVHD and bleeding were individually associated with reduced survival, with profound additive adverse effect: median survival in 221 nonbleeding non-GVHD was >83.2 months, GVHD nonbleeding (39 patients) had median of 10.6 months, bleeding non-GVHD (99 patients) had median of 4.3 months, and median survival of the GVHD bleeding group (85 patients) was 3.2 months. CONCLUSIONS: Our results support an association of bleeding with acute GVHD, suggesting that GVHD is a risk factor for bleeding after BMT. The occurrence of bleeding clearly identified poor outcome subgroup within GVHD, suggesting further evaluation for clinical application of bleeding in the assessment of GVHD severity.

Acute Disease↗
PubMed1999

Engineering hematopoietic grafts using elutriation and positive cell selection to reduce GVHD.

A systematic approach to hematopoietic graft manipulation has minimized several of the variables inherent to allogeneic BMT. Through this approach, we have been able to significantly impact on morbidity and quality of life following allogeneic transplantation. Acute and chronic GVHD, blood product and antibiotic usage, in patient hospitalization, acuity, costs and survival (especially in patients older than 40) have been improved. The HLA barrier still presents a formidable obstacle to achieving a more widespread use of this therapy. The complications encountered in HLA matched/TCD grafts occur with even greater magnitude in the HLA-mismatched or unrelated donor setting. Several centers are now engaged in studies using TCD grafts that are augmented with high doses of CD34+ cells to ensure engraftment while reducing the incidence of GVHD (50-53). Mobilized allogeneic PBSC appear to be an excellent source of stem cells for BMT (5,6). The earlier reports showed decreased rates of GVHD, despite having T cell burdens 10 times higher than those found in unmanipulated bone marrow. However, several of these centers now report an unacceptably high incidence of chronic GVHD (along with its attendant morbidity) following allogeneic PBSC transplantation (54-55). Initial results of TCD in these PBSC grafts using CD34+ selection are disappointing in that recipients developed unexpectedly high incidences of both acute and chronic GVHD (56). No doubt, significant differences exist between marrow and PBSC ancillary cell populations. For example, two laboratories now report the presence of natural suppressor cells in these allogeneic PBSC products in both mice (57) and humans (58). Thus, the same, step-wise approach would be expected to improve graft performance when using PBSC, cord blood, fetal tissue, xenografts or genetically engineered products as a stem cell source. Indeed, there are new reports of improved clinical outcome (especially in the incidence of GVHD) in the PMRD setting using both CD34+ selected (59) and sequential CD34+/CD2+ selected (60) PBSC grafts. It is hoped that future graft engineering approaches will be as successful as previous studies and will extend this form of therapy to an even larger patient population.

Animals↗
PubMed1999

Effectiveness of rotor off fraction in allogeneic murine bone marrow transplantation with complete disparity of major histocompatibility.

Counterflow centrifugal elutriation (CCE) has been a highly efficient physical method for separating T cells from bone marrow (BM) without impairing cell function and yield. To investigate the usefulness of CCE, the hematopoietic potential as well as the level of T cell contamination in rotor-off (R/O) fraction of BM was studied using a murine bone marrow transplantation (BMT) model [C3H/He (H-2k)-->BALB/C (H-2d)]. The total recovery of cells after CCE procedure was 71.4%. Morphologically, R/O fraction contained abundant mononuclear cells and a few lymphocytes. The numbers of colony forming unit for granulocyte/monocyte (CFU-GM), Sca-1+ cells, and T cells were compared among four fractions of CCE (fractions at flow rate of 17, 25, 28 mL/min, and R/O fraction). The number of CFU-GM per 10(5) nucleated cells in each fraction were significantly higher in R/O fraction (331.3 +/- 34.4) compared to unfractionated marrow (UM) (21.1 +/- 1.3) and fraction of 17 mL/min (FR 17) (23.7 +/- 2.2 ) (chi2 = 0.0044). Neither fraction of 25 mL/min (FR 25) nor fraction of 28 mL/min (FR 28) contained CFU-GM colonies. The concentration of Sca-1+ cells in R/O fraction was significantly higher (1.96-fold) than UM (p < 0.05), and 80.0 +/- 10.1% of Sca-1+ cells in UM were recovered in R/O fraction; 88.1% of Thy-1.2+ T cells were eliminated in R/O fraction (p < 0.05). Mice receiving UM after lethal irradiation (875cGy) suffered from severe graft-versus-host disease (GVHD) and all five died within 7 days after BMT procedure (Group A). Of interest, mice receiving mixture of R/O fraction with lymphocyte-rich fraction (FR 25 plus FR 28) to equalize T cell number as UM, developed severe GVHD and four out of five died (probability of survival; 20%) (Group B). Mice receiving R/O fraction had mild GVHD and four out of five survived for at least 90 days (probability of survival; 80%) (Group C). In group C, probability of survival (p = 0.0006) was higher, and severity of GVHD (p = 0.0043) and progression rate of GVHD (p = 0.02) was lower. In conclusion, the elutriated R/O fraction cells of BM have the advantages of stable engraftment and tolerable GVHD in murine allogeneic BMT with complete major histocompatibility disparity. This could be directly applicable to patients with high risk of GVHD and graft failure in upcoming clinical trials.

Animals↗
PubMed1999

Philadelphia chromosome-negative engraftment after autologous transplantation with granulocyte-macrophage colony-stimulating factor for chronic myeloid leukemia.

Autologous bone marrow transplantation (BMT) has not been curative in chronic myeloid leukemia (CML), because of the inability to purge CML from the autograft and the absence of the allogeneic T cell-mediated antileukemic activity. However, recent advances demonstrate that normal progenitors can be selected from CML marrows by a variety of techniques, including isolation by their small size. Furthermore, we found that myeloid growth factors have a potent antileukemic effect against CML progenitors in vitro by inducing their terminal differentiation. Based on these data, we initiated a trial of autologous BMT in patients with high-risk CML. Autografts were processed in an attempt to enrich for normal progenitors, first by isolating small cells by counterflow centrifugal elutriation and then incubating them in granulocyte-macrophage colony-stimulating factor (GM-CSF) for 72 hours. After a conditioning regimen of busulfan and cyclophosphamide, all patients received GM-CSF daily for 2 months. The median age of the 13 patients in the trial was 45 years (range 17-56 years). The median duration of disease before BMT was 24 months (range 13-72 months). Eight patients were in chronic phase (CP), and five were in accelerated phase (AP). All patients failed to achieve a cytogenetic response to interferon-alpha and were 100% Philadelphia chromosome (Ph)+ before BMT. There were three transplant-related deaths, all AP patients. All of the remaining 10 patients engrafted with some degree of Ph- hematopoiesis; despite high-risk features, nine patients engrafted 100% Ph-. All patients relapsed cytogenetically at a median of 6 months (range 4-22 months). These results demonstrate that autologous BMT can consistently induce complete Ph- engraftment in CP patients. GM-CSF appears to produce a clinical antileukemic effect against CML after autologous BMT.

Adolescent↗
PubMed1999

Collection of peripheral blood progenitor cells (PBPC) based on a rising WBC and platelet count significantly increases the number of CD34+ cells.

The kinetics of mobilization and optimal timing of peripheral blood progenitor cell (PBPC) collection were evaluated in 190 patients with multiple myeloma undergoing stem cell harvest after mobilization with cyclophosphamide, prednisone and G-CSF. There was a strong correlation between the WBC count and the number of CD34+ cells circulating in peripheral blood (r = 0.875). Initiating leukapheresis based on rising WBC and platelet counts rather than on a fixed day increased the mean number of CD34+ cells 115% (9.7 to 20.9 x 10(6) CD34+ cells/kg; P = 0.010) for the total of all leukaphereses and 59% for the total of all CD34-selected products (5.1 to 8.1 x 10(6) CD34+ cells/kg; P = 0.011). Although the yield and purity of the CD34-selected product were not significantly affected (P > or = 0.071), the percentage of patients with concentrations of CD34+ cells in the initial leukapheresis of > 1% increased from 47% to 70% (P = 0.004). The mean purity of the selected product was related to the starting percentage: 48.9% if < 1% and 81.5% if > or = 1% (P < 0.001). Collection of stem cells based on rising WBC and platelet counts significantly increased the number of CD34+ cells in leukaphereses and CD34-selected products in comparison with collection on a fixed day.

Adult↗
PubMed1998

Chemotherapy does not nullify the ability of donor lymphocyte infusions to mediate graft-versus-host reactions.

Two patients with multiple myeloma in relapse after allogeneic BMT received donor lymphocyte infusions (DLI) but later required chemotherapy for treatment of myeloma-related complications. In both patients, recovery from chemotherapy-induced aplasia was accompanied by manifestations of graft-versus-host reactions. The first patient developed grade II acute GVHD and a complete remission which has lasted >22 months. The second patient developed grade III acute GVHD but died with co-existing GVHD and extensive extramedullary myeloma. These results demonstrate that chemotherapy does not nullify the ability of donor lymphocytes to mediate graft-versus-host reactions.

Adult↗
PubMed1998

Frequent detection of tumor cells in hematopoietic grafts in neuroblastoma and Ewing's sarcoma.

Many poor-risk neuroblastomas and tumours of the Ewing's sarcoma family (ET) recur despite autologous transplants. Recurrence may be due to tumor cells contained in the BM harvests or PBSC harvests. The objectives of this prospective study were to: (1) determine the incidence and degree of tumor cell contamination in paired BM and PBSC harvests; and (2) determine the efficacy of tumor cell purging by immunomagnetic CD34+ cell selection. 198 samples from 11 consecutive patients with neuroblastoma or Ewing's sarcoma were analyzed. We assayed tumor contamination by RT-PCR assay for PGP 9.5, plus immunohistochemistry for neuroblastoma-specific antigens (the latter in neuroblastoma only). None of these patients had tumor cells detected in their BM by clinical histology immediately before BM or PBSC harvests. However, 82% of PBSC and 89% of backup BM harvests were contaminated with tumor by RT-PCR and/or immunocytochemistry assays. Unselected PBSC and BM harvests contained similar quantities of tumor cells (median, approximately 200000 cells). Cyclophosphamide plus G-CSF mobilization did not affect the incidence or level of contamination in PBSC harvests, as compared to blood obtained before mobilization. Immunomagnetic CD34+ cell selection depleted tumor cells by a median of 3.0 logs for PBSC, and 2.6 logs for BM harvests.

Adolescent↗